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Abstract
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A new nanocomposite material composed of reduced graphene oxide-supported rhodium nanoparticles (rGORhNP)
and its photocatalytic activity have been examined for the photoassisted reduction of CO2 with H2. A
continuous two-step method has been performed in order to prepare rGO-RhNP. In this method graphene oxide
were reduced with NaBH4 and Rh nanoparticles deposited in situ on the 2D carbon nanomaterial planar sheets.
An optimal Rh loading of 18 wt% was observed, leading to the highest CH4 formation rate (814.38 μmol
CH4.gRh−1 h−1 at 175 °C) and quantum efficiency of 2.55%. The deliterious effect of H2O formation during the
reaction on the photocatalytic activity has been apparent and additional evidences confirmed that H2O desorption
was one of the reasons why the system needed heating. Under constant flow operation, unwanted molecules
of water were better desorbed from the rGO-Rh2O3/Rh photocatalyst than in the batch mode, continuing
with a regular specific CH4 formation rate of 307.45 μL h−1 for 50 mg of rGO-RhNP catalyst with a residence
time of 2.7 s. Quenching trials using dimethylaniline, anisole and p-xylene as potential electron donors are
congruent with a photo assisted mechanism
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